| dc.description.abstract |
ABSTRACT
Aerosols are microscopic liquid or solid particles which enter the atmosphere through natural
and man-made processes. Atmospheric aerosols influence the Earth’s weather and climatic
system in many ways, both directly and indirectly, although the magnitude of this influence
remains uncertain even today (IPCC, 2007). Interactions between aerosols and clouds have
become the subject of scientific research because of the importance of clouds in controlling
climate. In this thesis, we have examined the temporal variations (time series analysis) in aerosol
particles over Ethiopia and the impact of these variations on various optical properties of clouds
using Moderate Resolution Imaging Spectroradiometer (MODIS) data from January 2003 to
December 2018. The maximum aerosol optical depth (AOD) was found at summer period with
minimum values in winter. During summer air temperature is high leads to hold abundant
atmospheric water vapor facilitated the hygroscopic growth of aerosols. We then analyzed the
relationships between AOD and other cloud parameters, namely water vapour (WV), cloud
fraction (CF), cloud top temperature (CTT) and cloud top pressure (CTP) to provide a better
understanding of aerosol–cloud interaction. The correlation between AOD and cloud fraction
(CF), water vapor (WV) was positive for Ethiopian continent, while negative correlation with
cloud top temperature (CTT) and cloud top pressure (CTP).
Key words: MODIS, AOD, CF, CTP, CTT, WV and Ethiopia |
en_US |